I actually have some doubts on this jacket being real seersucker, but I've only seen the real thing on fabric swatches, so I'm not sure. Only time will tell I guess, if the wrinkly texture fades away... not that I care much, because it's extremely lightweight and comfortable for warm weather - I wouldn't mind if it was just a bengal stripe.
The wrinkly texture is the point--that's basically what seersucker is. Otherwise, like you said, it'd just be a bengal stripe.
I love seersucker. I'll have to have a seersucker jacket made one of these days.